Enhancement in performance of DHTprecoding over WHT for EC companded OFDM in wireless networks

Autor: D. N. V. S. L. S. Indira, Prabhakara Rao Kapula, Asisa Kumar Panigrahy, B. Prasad, Dumpa Prasad, A. Lakshmi Narayana
Rok vydání: 2021
Předmět:
Zdroj: Applied Nanoscience. 13:1515-1530
ISSN: 2190-5517
2190-5509
Popis: In this paper, a new hybrid methodology that combines precoding transform and companding transforms is being proposed for next-generation heterogeneous wireless networks. This method will improve the performance of the orthogonal frequency division multiplexing (OFDM) system by reducing the Peak to average power ratio (PAPR). A hybrid methodology that combines exponential companding (EC), which is a non-linear companding technique with Discrete Hartley Transform (DHT), as well as Walsh Hadamard Transform (WHT), is proposed and investigated. When the three simulated results are compared with original OFDM signal, piecewise linear companding shows an improvement factor of 28.8% over the original OFDM signal. Exponential companding is having an improvement factor of 33.49% over the original OFDM signal. Walsh Hadamard transform combined with exponential companding shows an improvement factor of 34.99% over OFDM. Discrete Hartley Transform combined with Exponential Companding is having an improvement factor of 38.09% over OFDM. The two proposed methods do not introduce any In-band distortion as well as Out-of-band Radiation when compared to the existing technique PLC (Meixia et al. in IEEE Trans Broadcast 60(3):532-539, 2014) which can be observed from the PSD analysis. Among the two proposed methods, the DHT precoded OFDM with the EC system shows significant BER improvement over the remaining methods. In addition to AWGN Channel, this proposed method shows significant BER performance improvement under the SUI-1 to 6 (WiMAX Channels) channels making use of 256-QAM as the modulation technique. As we move to a higher-order constellation, it is possible to transmit more bits per symbol; in such cases, the proposed technique will achieve better improvement in the performance of BER over all the existing techniques.
Databáze: OpenAIRE
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